hlist_add_after broken?

["Pedro Emanuel M. D. Pinto" <pepinto@student.dei.uc.pt>]

There is an inline function (hlist_add_after) in include/linux/list.h which I 
believe is broken. The algorithm used doesn't make sence to me so if it 
actually ok I would appreciate if someone could explain it to me. Below is a 
patch I made against version 2.6.1 of what I believe is a working function.

regards,

Pedro Pinto


--- include/linux/list.h.orig	2004-04-17 23:13:42.901457376 +0100
+++ include/linux/list.h	2004-04-17 23:17:28.943093824 +0100
@@ -525,9 +525,12 @@
 static __inline__ void hlist_add_after(struct hlist_node *n,
 				       struct hlist_node *next)
 {
-	next->next	= n->next;
-	*(next->pprev)	= n;
-	n->next		= next;
+	next->next = n->next;
+	n->next = next;
+	next->pprev = &n->next;
+
+	if(next->next)
+		next->next->pprev  = &next->next;
 }

 #define hlist_entry(ptr, type, member) container_of(ptr,type,member)